Movable barrier operators of various kinds are known in the art. In general, such operators serve to effect selective movement of a movable barrier (including but not limited to garage doors of various kinds, rolling shutters, and other horizontally or vertically sliding, moving, or pivoting doors, gates, arms, and the like) between at least a first position and a second position (such as between an opened and a closed position). In many application settings it is desired or required to detect when such a movable barrier encounters an obstacle and to respond accordingly (such as by ceasing movement or by reversing movement away from the detected obstacle). Many movable barrier operators detect applied force when moving a corresponding movable barrier to facilitate the detection of an obstacle in the path of the movable barrier. For example, a presently sensed force reading that exceeds a predetermined allowable force level can evidence the presence of such an obstacle.
Unfortunately, the amount of force reasonably required to initiate or maintain movement of a given movable barrier typically changes with a multitude of factors. These include but are not limited to a specific present location of the movable barrier with respect to its track, temperature, humidity, age, oxidation, presence or lack of lubricity or contaminants, and so forth. Therefore, a single maximum applied force threshold will sometimes prove unsatisfactory, as such a universal threshold can be too low to accommodate applied force needs under some circumstances and inappropriately high under other circumstances.
Therefore, movable barrier operators that use multiple applied force thresholds are available to better meet such challenging circumstances. In some embodiments the movable barrier operator uses different force thresholds during different travel segments. So configured the movable barrier operator uses a force threshold that will hopefully more appropriately correspond to the actual force requirements of a given movable barrier system at various locations during the controlled movement of that movable barrier. For example, a system that parses movable barrier travel into two discrete segments offers an opportunity to use two different corresponding force thresholds that better reflect the force requirements of a given installation.
Of course, the more segments that are supported, the more accurately one can provide a corresponding maximum force threshold. That is, the maximum force threshold can more closely track the normal expected force requirements exhibited by a given movable barrier. This, in turn, can yield improved sensitivity and/or reliable detection of obstacles. By providing maximum permitted thresholds that track relatively closely with expected force requirements, deviant performance is more readily and quickly sensed.
Unfortunately, supporting a high number of travel segments (and hence a high quantity of corresponding force information) corresponds to a large quantity of data. Movable barrier operators, however, comprise a relatively price-sensitive commodity. Providing a large memory to support retention of a large quantity of force-related information will typically increase the relative cost of the movable barrier operator. This has the general effect of precluding the use of high-resolution force-sensitive capability in lower tier movable barrier operators and hence denying the corresponding systems the benefits of such an approach.
Skilled artisans will appreciate that common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments.